This invention relates to an optical card for carrying out optical recording and a process for preparing the same.
There is an optical recording playback system wherein a thin film of low melting metals such as tellurium and bismuth is provided on a substrate, the laminate is irradiated with a laser beam or the like to change a portion of the thin film to carry out recording, and the recorded information is subjected to optical playback. Such an optical recording playback system has an advantage that the recorded information density is dramatically higher as compared with that of prior art magnetic systems, and IC systems examined in recent years.
However, in the optical recording playback system described above, a laser beam is used and therefore high technology is required in controlling the laser beam. Further, the optical recording playback system is unsuitable for mass production. Particularly, in order to apply the optical recording playback system to cards which are issued in a large amount (ID cards such as bank's cash cards and credit cards), it is required to develop materials and systems which are cheaper and suitable for mass production.
Further, the deposition of soil onto recorded portions, and the damage of the recorded portions are undesirable in optical playback from the standpoint of high recording density.